NAME

pthread_condattr_destroy, pthread_condattr_init - destroy and initialize the condition variable attributes object

SYNOPSIS

[THR] #include <pthread.h>

int pthread_condattr_destroy(pthread_condattr_t *attr);
int pthread_condattr_init(pthread_condattr_t *attr);

DESCRIPTION

The pthread_condattr_destroy() function shall destroy a condition variable attributes object; the object becomes, in effect, uninitialized. An implementation may cause pthread_condattr_destroy() to set the object referenced by attr to an invalid value. A destroyed attr attributes object can be reinitialized using pthread_condattr_init(); the results of otherwise referencing the object after it has been destroyed are undefined.

The pthread_condattr_init() function shall initialize a condition variable attributes object attr with the default value for all of the attributes defined by the implementation.

Results are undefined if pthread_condattr_init() is called specifying an already initialized attr attributes object.

After a condition variable attributes object has been used to initialize one or more condition variables, any function affecting the attributes object (including destruction) shall not affect any previously initialized condition variables.

This volume of IEEE Std 1003.1-2001 requires two attributes, the clock attribute and the process-shared attribute.

Additional attributes, their default values, and the names of the associated functions to get and set those attribute values are implementation-defined.

RETURN VALUE

If successful, the pthread_condattr_destroy() and pthread_condattr_init() functions shall return zero; otherwise, an error number shall be returned to indicate the error.

ERRORS

The pthread_condattr_destroy() function may fail if:

[EINVAL]

The value specified by attr is invalid.

The pthread_condattr_init() function shall fail if:

[ENOMEM]

Insufficient memory exists to initialize the condition variable attributes object.

These functions shall not return an error code of [EINTR].

EXAMPLES

None.

APPLICATION USAGE

None.

RATIONALE

See pthread_attr_init() and pthread_mutex_init().

A process-shared attribute has been defined for condition variables for the same reason it has been defined for mutexes.

FUTURE DIRECTIONS

None.

SEE ALSO

pthread_attr_destroy(), pthread_cond_destroy(), pthread_condattr_getpshared(), pthread_create(), pthread_mutex_destroy(), the Base Definitions volume of IEEE Std 1003.1-2001, <pthread.h>

CHANGE HISTORY

First released in Issue 5. Included for alignment with the POSIX Threads Extension.

Issue 6

The pthread_condattr_destroy() and pthread_condattr_init() functions are marked as part of the Threads option.